The basic adaptive filtering algorithm

is analyzed using the theory of weak convergence. Apart from some very special cases, the analysis is hard when done for each fixed

. But the weak convergence techniques are set up to provide much information for small

. The relevant facts from the theory are given. Define

by

on

. Then weak (distributional) convergence of

and of

is proved under very weak assumptions, where

as

. The normalized errors

are analyzed, where

is a "stable" point for the "mean" algorithm. The asymptotic properties of a projection algorithm are developed, where the

are truncated at each iteration, if they fall outside of a given set.